Disc sizing ???

[jarhead]

Roughly 70% of your braking is on the front.

After reading the above statement is it better to go with a larger disc on the front than the back, or can you have equally sized discs all around.

I may have made a mistake on my 68 Torino and bought too small of a disc (11.3) for the front. It was touted as a stock replacment kit for my car9 Kelsey-Hayes).

I have large drums ( 10 X 2.5 ) on the back that I plan to convert to discs someday.

This is the kit I bought.

http://www.discbrakeswap.com/The%20S...2008%20pdf.pdf

My Torino is not a track car, and has a mild 351, TKO 5 speed. It is morphing into a Pro -Tourer as I have the money, and time.

Thanks, Joe

https://lateral-g.net/forums/show...ghlight=torino

Thanks, Joe

[badazz81z28]

I don't understand why you would need a bigger disc on the back. Most of the braking power come from the front wheels. If I had to choose, bigger disc on the front or just make them equal. The bigger disc and piston area on the caliper is what you want to reduce heat, reduce brake fade, increased clamping force surface area.

[Rod P]

Originally Posted by jarhead

(11.3) for the front. It was touted as a stock replacment kit for my car9 Kelsey-Hayes).

I have large drums ( 10 X 2.5 ) on the back that I plan to convert to discs someday.

This is the kit I bought.

http://www.discbrakeswap.com/The%20S...2008%20pdf.pdf

My Torino is not a track car, and has a mild 351, TKO 5 speed. It is morphing into a Pro -Tourer as I have the money, and time.

Thanks, Joe

https://lateral-g.net/forums/show...ghlight=torino

Thanks, Joe

your fine Joe....just build on brother i used the stock camaro front disc and rear drums to autocross with for over a year

[jarhead]

Originally Posted by badazz81z28

I don't understand why you would need a bigger disc on the back. Most of the braking power come from the front wheels. If I had to choose, bigger disc on the front or just make them equal. The bigger disc and piston area on the caliper is what you want to reduce heat, reduce brake fade, increased clamping force surface area.

thanks for the information

Originally Posted by Rod P

your fine Joe....just build on brother i used the stock camaro front disc and rear drums to autocross with for over a year

thanks, would have never known that was possible

[mitch_04]

Well, I'm no expert but I try to listen to them!

First off, you want to figure out why larger rotors are "better". The larger rotors has 2 main benefits. The first, and probably most important, is increased mass. A larger rotor has more mass so it will take more &/or harder braking before it will heat up. This is assuming identical rotors except for diameter.

Second, leverage. A longer lever creates more torque, as anyone with a cheater on a breaker bar knows. The further away from center the pads are, the more leverage it will have to stop the spinning rotor.

The downsides to larger rotors is weight and packaging. The extra mass that keeps it from heating up also makes it harder to start when it's stopped and harder to stop once it's spinning. Just like heavier wheels, or any heavier spinning piece in the drivetrain, it robs acceleration. I can't remember the exact amount, but any extra weight that spins has double or triple or whatever the effect due to the rotation. Packaging is pretty self explanatory, gotta have room for the brakes!


So as far as your question goes...well... same size brakes or bigger in front will both work. Having a properly designed hydraulic system to apply the correct pressure at the wheels is more important, think of rotor size more as "endurance" than actually helping you slow more quickly...although they are related.

Ron Sutton has mentioned in one of his threads that he uses a relatively small rotor (11" or 12") in some of his race cars and it does just fine. You just need to figure out what exactly you are trying to accomplish with your build, and figure out what will meet your requirements best!